Momentary push button switch with improved non-conductive cam for normally retaining movable leaf spring contacts in a non-operative position

ABSTRACT

An electrical switch of the push-button type including an actuator movable through a switch housing, with the actuator providing a cam head which when in its original or unactuated position, physically separates the contact ends of the switch blades within the housing, thereby preventing undesirable closing of the switch resulting from shock, vibration, or teasing, while permitting a full actuating movement and harmless overtravel of the actuator so as to positively assure proper and complete switch blade closure.

United States Patent 1 Long [ MOMENTARY PUSH BUTTON SWITCH WITH IMPROVED NON-CONDUCTIVE CAM FOR NORMALLY RETAINING MOVABLE LEAF SPRING CONTACTS IN A NON-OPERATIVE POSITION [75] Inventor: Eric L. Long Waukegan, 111.

[73] Assignee: Cherry Electrical Products Corporation, Waukegan, 111.

22 Filed: June 18, 1971 211, Appl.No.: 154,512

[52] US. .Cl. ..200/159 A, 200/6 BB [51] Int. Cl. ..H01h 3/12, HOlh 13/62 [58] Field of Search ..200/1 A, 4, 5 R, 5 EB, 16 B,

200/16 R, 159 R, 159 A, 166 J, 167 A, 6 BB [56] References Cited UNITED STATES PATENTS 3,636,282 l/1972 Kirchdorf ..200/159 A X 1 Feb. 6, 1973 3,219,776 11/1965 Yerkovich ..200/159 A X 2,786,904 3/1957 Hewes et a1 ..200/167 A UX 3,165,612 1/1965 Bailey ..200/167 A X 2,870,273 1/1959 Merchant ..200/6 BB X 2,470,701 5/1949 Jacobs ....200/l59 A X 3,392,250 7/1968 Ziegler et a1 ..200/166 UX Primary ExaminerJ. R. Scott Att0rneyEdward C. Threedy [57] ABSTRACT An electrical switch of the push-button type including an actuator movable through a switch housing, with the actuator providing a cam head which when in its original or unactuated position, physically separates the contact ends of the switch blades within the housing, thereby preventing undesirable closing of the switch resulting from shock, vibration, or teasing, while permitting a full actuating movement and harmless overtravel of the actuator so as to positively assure proper and complete switch blade closure.

8 Claims, 11 Drawing Figures I PATENTED EB 6 7 SHEET 10F 2 PATENTEUFEB 6 I973 3,715,545 SHEET 20F 2 IN UENTOR/ Ema-17. ,Zwvc;

my Wmw MOMENTARY PUSH BUTTON SWITCII WITH IMPROVED NON-CONDUCTIVE CAM FOR NORMALLY RETAINING MOVABLE LEAF SPRING CONTACTS IN A NON-OPERATIVE POSITION SUMMARY THE INVENTION A push-button electrical switch wherein the switch blades are biased into an original closed position with respect to each other and normally held in an open position by an actuator movable through a switch housing. The actuator is yieldably maintained in its original position by a spring situated in its path of longitudinal movement. Within the switch housing the actuator provides a cam head that engages and constrains one switch blade against its normal biased displacement into contact with the other stationary switch blade, thus physically maintainingthe switch in an open condition and preventing undesirable closing of the same through shock, vibration, or teasing. The cam head may, if required, be so formed as to provide a momentary restraining movement against the biased switch blade so as to effect a tactile feel upon the actuator, allowing the operator thereof to be apprised of the necessary actuating movement of the actuator to achieve complete and positive switch closure.

GENERAL DESCRIPTION The most advantageous embodiment of the electrical push-button switch of this invention is illustratively shown in the accompanying drawings, in which:

FIG. 1 is a perspective view of the electrical pushbutton switch;

FIG. 2 is a side elevational sectional view of the pushbutton switch;

FIG. 3 is a side elevational view of the switch components in an operated or closed position;

FIG. 4 is a perspective view of certain of the switch components in their assembled relation;

FIG. 5 is a perspective view of the push-button actuator of this invention;

FIG. 6 is a perspective view of the movable biased switch blade;

FIG. 7 is a perspective view of the stationary switch blade; j

' FIG. 8 is a plan view of one face of the bottom plate of the switch;

FIG. 9 is a fragmentary bottom view of the interior of the switch housing;

FIG. 10 is a fragmentary side elevational view of a modified form of the switch actuator;

FIG. 11 is a fragmentary side elevational view similar to FIG. 10, but showing the parts in an operated or closed switch position.

This invention relates to a push-button type switch which may be readily used in what is known askeyoperated" equipment, such as typing, printing, calculating, and computer machines. Heretofore these types of equipment included a push-button switch that included a movable magnet that operated a sealed reed switch. It was found that in certain installations the employment of reed switches was undesirable, in that they 'could be accidentally operated or closed through shock, vibration, or accidental teasing of the push-button switch by the operator.,As most of these switches complete an electrical circuit, such accidental closure effected erroneous operation of the equipment.

To overcome the above referred to objections to reed switches, there is disclosed herein a push-button switch 10 which includes a hollow housing 11 closed by a base plate 12.

Referring to FIGS. 4 and 8, it is shown that the base plate 12 on one face thereof provides a raised formed platform 13 which includes parallel grooves 14 and 15, certain of which have open communication with apertures 16 and 17, respectively, formed through the base plate 12. A center recess 18 is provided in the one face of the base plate 12 which defines an area of separation between the grooves 14 and 15 and the apertures 16 and 17, for the purpose hereinafter made apparent.

The hollow housing 11, as shown in FIG. 9, provides channeled guide abutments 19 on confronting faces of oppositely disposed side walls 20. Restraining depressions 21 are formed in the inner face of the top wall 22 adjacent to the center opening 22' formed therein. The channeled guide abutments 19 are adapted to embrace laterally projecting shoulders 23 provided by the raised platforml3 of the base plate 12, while the formed corners of the housing 11 confront adjacent formed corners of the platform 13, when the base plate 12 is mounted to the hollow housing 11 to close and seal the same, as shown in FIGS. 1 and 2.

Mounted on the base plate 12 is a stationary contact plate 24 which provides a depending terminal 25 which is adapted to be projected through the aperture 17 formed in the base plate 12. On the opposite side edges of the stationary contact plate 24, there is provided a pair of pointed retaining lugs 26 which are adapted to be forced into frictional contact with the opposite end edges which define the grooves 15 formed in the base plate 12. By this means the stationary contact plate 24 is fixedly attached to the base plate 12 so as to extend in a vertical relation with respect thereto.

Adjacent the top of the stationary contact plate 24 is a switch contact 27 which is contained in the centerline of the contact plate 24 immediately beneath a top shoulder 28 provided by the top edge of the contact plate 24. This top shoulder 28 is adapted to be positioned within the restraining depression 21 formed in' the top wall 22 of the hollow housing 11 to cooperate with the mounting of the contact plate 24 to the base plate 12, to maintain the contact plate 24 in a rather rigid fixed position. 1

It should be noted that in the drawings, the illustrated push-button switch 10 is of the double-pole type, which means that there is a duplication of parts described herein. The duplicated parts in obvious instances will be referred to by identical reference numerals.

A switch blade 29 is adapted to be mounted in the groove 14 formed in the base plate 12, and provides a depending terminal 30 adapted to be projected through the aperture 16 formed in the groove 14. The switch blade 29 provides laterally extending enlarged base sections 31 which provide on their outer edges, pointed retaining lugs 32 which are adapted to be frictionally projected into the end walls defining the groove 14, so as to mount the switch blade 29 to the base plate 12. Adjacent the upper end portion of the switch blade 29 are a pair of laterally extending arms 33 which provide substantially U-shaped distal ends 34.

A switch contact 35 is mounted at the upper free end of the switch blade 29 and has a longitudinal length which is so disposed as to be perpendicular to the longitudinal length of the switch contact 27 provided by the stationary contact 24, such that there would be cross contacts between the two when they are permitted to engage each other. It should be noted that the switch blade 29 from a line extending through the blade 29 adjacent to the top edge of the laterally extending enlarged base sections 31, is bent out of its normal longitudinal length so as to be biased into the direction of and so as to seek contact with the fixed stationary contact plate 24. This embodiment is shown clearly in FIG. 4, and such functional relation will be hereinafter more fully described.

The switch structure includes as an operative component an actuator 36 comprising a rectangularly shaped body 37 providing on its top edge a frictional in sert 38 adapted to be pressfitted into a hollow internal shank 39 of an external switch button 40. The bottom edge of the body 37 is notched as at 41 to provide a center stud 42, the purpose of which will be hereinafter made apparent.

Extending laterally from each side edge of the body 37 are shoulders 43 that support cam heads 44 that extend transversely to the longitudinal length of the actuator 36. These cam heads 44 are substantially trapezoidal in form and, as such, provide downwardly and outwardly inclined edge surfaces 45 which terminate in a short vertical wall section 46.

A second set of trapezoidally formed sections 47 of a reduced size are provided by the actuator 36 below the cam heads 44 and carry on their outer surfaces guide lugs 48 utilized to, guide the actuator 36 during its reciprocal movement through the hollow housing 11.

It should be noted that the combined width of the body 37 and shoulders 43 is such that the transversely extending cam heads 44 will lie outboard of the side longitudinal edges of the stationary contact plate 24 and in contact with the U-shaped distal ends 34 of the biased switch blade 29, as seen in FIGS. 2 and 3.

The switch is partially assembled in the manner shown in FIG. 4, which has been previously described. The actuator 36 has a portion of its body 37 projected through the opening 22 formed in the top wall 22, and with the remaining portion of the body disposed between the stationary contact plates 24, as seen in FIGS. 2 and 3. A coil spring 49 is seated in the circular recess 18 formed in the base 12 and embraces the center stud 42 provided by the bottom edge of the body 37 of the actuator 36. This spring normally urges the actuator 36 in its extended position with respect to the switch housing 11 as shown in FIGS. 1 and 2. The guide lugs 48 will ride in the channel guides 19 formed on the inner wall surfaces of the side walls of the hollow housing 11 and cooperate with the opening 22 in guiding the actuator 36 reciprocally.

In its normal or unactuated condition wherein the switch contacts are open, the components of the switch are as shown in FIG. 2. Upon applying pressure to the switch button 40 to effect movement of the actuator 36 against the coil spring 49, the cam heads 44 will be moved out of contact with the U-shaped distal ends 34 of the switch blade 29, permitting the same to be biased into contact with the stationary contact plate 24, as shown in FIG. 3. Upon release of the actuating force from the switch button 40, the coil spring 49 will return the actuator 36 to its original position wherein the cam heads 44 will engage the distal ends 34 of the switch blade 29 and physically separate its contact 35 from the contact 27 of the stationary contact plate 24.

In FIGS. 10 and 11 there is shown a modified form wherein the switch is provided with a structure which produces a tactile feel on the actuating movement of the actuator 36. To achieve the tactile feel, the

distended end of one ofthe cam heads 44 is notched as at 50 to provide a right-angle shoulder 51. This shoulder 51, upon movement of the actuator 36, will engage the corresponding flat surface 52 of the U- shaped distal end 34 of one of the switch blades 29, and thus yieldably resist further movement of the actuator 36 until sufficient movable force has been applied thereto to overcome the mating of the surfaces 51 and 52.

From the foregoing, it is apparent that this invention discloses a push-button type switch which has a positive action and by reason of its construction provides a switch housing which is of a compact size, being of a length less than that required when a conventional reed switch is used, and permitting a composition switch board to be constructed from a multitude of key switches taking up a lesser total area and requiring a lesser inclined surface.

It should be pointed out that the top wall 22 of the switch housing tapers downwardly and outwardly from a raised shoulder 53 which surrounds and defines the opening 22' formed therein. This taper of the top wall 22 prevents accumulation of dirt, dust, and moisture which normally would tend to find its way through the opening 22' and into the interior of the switch housing.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described the invention, what I claim as new and desire to protect by Letters Patent is:

1. An electric push-button switch comprising a. a hollow housing including an actuator reciprocally movable therethrough, means within said hollow housing for yieldably resisting movement of the actuator in one direction therethrough,

c. a stationary contact plate carried in a fixed position within said housing and extending in a plane parallel to the movement of the actuator therethrough, d. a switch blade within said housing and having one end normally biased into closed contact position with said stationary contact plate,

e. mans provided by said actuator in contact with said switch blade and movable between it and said stationary contact plate and restraining said switch blade against movement into contact with said stationary contact plate when said actuator is in its yieldably held position by said first-mentioned means,

f. guide means carried by said actuator and cooperating with elongated slots provided in certain sides of the housing and extending longitudinally of said stationary contact and said switch blade for directing the reciprocal movement of said actuator through said housing,

g. and means on said switch blade in the path of movement of said actuator and cooperating therewith to restrain said switch blade from contact with said stationary contact plate when said actuator is in its yieldably held position.

2. An electrical push-button switch as defined by claim 1 wherein said means carried by the base plate within the hollow housing for yieldably resisting move ment of the actuator in one direction comprises a coil spring, and further defined by having means on said base plate and on the actuator for maintaining said coil spring in axial alignment with the longitudinal axis of the actuator.

3. An electrical push-button switch as defined by claim 1 wherein said means on the actuator in contact with said one end of said switch blade and restraining it against movement in contact with said stationary contact plate, comprises cam surfaces which extend transversely to the longitudinal plane of the actuator and to either side of the longitudinal edges of said stationary contact plate.

4. An electrical push-button switch as defined by claim 1 wherein said means provided by said switch blade in the path of movement of' said restraining means provided by the actuator comprises formed distal end members extending laterally from opposite longitudinal edges of said switch blade.

5. An electrical push-button switch as defined by claim 3 wherein said means provided by said switch blade in the path of movement of said cam surfaces provided by the actuator comprises formed distal end members extending laterally from the longitudinal edges of said switch blade and into the path of movement of said cam surfaces provided by the actuator.

6. An electrical push-button switch as defined by claim 1 further defined by the inclusion of guide means between the hollow housing and the actuator for-guiding the actuator during its reciprocal movement into the hollow housing.

7. An electrical push-button switch as defined by claim 5 further including guide means between the hollow housing and the actuator for guiding the actuator during its reciprocal movement into the hollow housing.

8. An electrical push-button switch as defined by claim 1 further defined by the inclusion of means on the base plate cooperating with means provided by the hollow housing for positioning said stationary contact plate and said switch blade in operative alignment with the'reciprocally movable actuator. 

1. An electric push-button switch comprising a. a hollow housing including an actuator reciprocally movable therethrough, b. means within said hollow housing for yieldably resisting movement of the actuator in one direction therethrough, c. a stationary contact plate carried in a fixed position within said housing and extending in a plane parallel to the movement of the actuator therethrough, d. a switch blade within said housing and having one end normally biased into closed contact position with said stationary contact plate, e. mans provided by said actuator in contact with said switch blade and movable between it and said stationary contact plate and restraining said switch blade against movement into contact with said stationary contact plate when said actuator is in its yieldably held position by said first-mentioned means, f. guide means carried by said actuator and cooperating with elongated slots provided in certain sides of the housing and extending longitudinally of said stationary contact and said switch blade for directing the reciprocal movement of said actuator through said housing, g. and means on said switch blade in the path of movement of said actuator and cooperating therewith to restrain said switch blade from contact with said stationary contact plate when said actuator is in its yieldably held position.
 1. An electric push-button switch comprising a. a hollow housing including an actuator reciprocally movable therethrough, b. means within said hollow housing for yieldably resisting movement of the actuator in one direction therethrough, c. a stationary contact plate carried in a fixed position within said housing and extending in a plane parallel to the movement of the actuator therethrough, d. a switch blade within said housing and having one end normally biased into closed contact position with said stationary contact plate, e. mans provided by said actuator in contact with said switch blade and movable between it and said stationary contact plate and restraining said switch blade against movement into contact with said stationary contact plate when said actuator is in its yieldably held position by said first-mentioned means, f. guide means carried by said actuator and cooperating with elongated slots provided in certain sides of the housing and extending longitudinally of said stationary contact and said switch blade for directing the reciprocal movement of said actuator through said housing, g. and means on said switch blade in the path of movement of said actuator and cooperating therewith to restrain said switch blade from contact with said stationary contact plate when said actuator is in its yieldably held position.
 2. An electrical push-button switch as defined by claim 1 wherein said means carried by the base plate within the hollow housing for yieldably resisting movement of the actuator in one direction comprises a coil spring, and further defined by having means on said base plate and on the actuator for maintaining said coil spring in axial alignment with the longitudinal axis of the actuator.
 3. An electrical push-button switch as defined by claim 1 wherein said means on the actuator in contact with said one end of said switch blade and restraining it against movement in contact with said stationary contact plate, comprises cam surfaces which extend transversely to the longitudinal plane of the actuator and to either side of the longitudinal edges of said stationary contact plate.
 4. An electrical push-button switch as defined by claim 1 wherein said means provided by said switch blade in the path of movement of said restraining means provided by the actuator comprises formed distal end members extending laterally from opposite longitudinal edges of said switch blade.
 5. An electrical push-button switch as defined by claim 3 wherein said means provided by said switch blade in the path of movement of said cam surfaces provided by the actuator comprises formed distal end members extending laterally from the longitudinal edges of said switch blade and inTo the path of movement of said cam surfaces provided by the actuator.
 6. An electrical push-button switch as defined by claim 1 further defined by the inclusion of guide means between the hollow housing and the actuator for guiding the actuator during its reciprocal movement into the hollow housing.
 7. An electrical push-button switch as defined by claim 5 further including guide means between the hollow housing and the actuator for guiding the actuator during its reciprocal movement into the hollow housing. 